问答题：微分方程y’+xy2-y2=1-x的通解为______．

题型：单项选择题

Passage Four

Social change is more likely to occur in societies where there is a mixture of different kinds of people than in societies where people are similar in many ways. The simple reason for this is that there are more different ways of looking at things present in the first kind of society. There are more ideas, more disagreements in interest, and more groups and organizations with different beliefs. In addition, there is usually a greater worldly interest and greater tolerance in mixed societies. All these factors tend to promote social change by opening more as of life to decision. In a society where people are quite similar in many ways, there are fewer occasions for people to see the need or the opportunity for change because everything seems to be the same. And although conditions may not be satisfactory, they are at least customary and undisputed.
Within a society, social change is also likely to occur more frequently and more readily in the material aspects of the culture than in the non-material, for example, in technology rather than in values; in what has been learned later in life rather than what was learned early; in the less basic and less emotional aspects of society than in their opposite; in the simple elements rather than in the complex ones; in form rather than in substance; and in elements that are acceptable to the culture rather than in strange elements.
Furthermore, social change is easier if it is gradual. For example, it comes more readily in human relations on a continuous scale rather than one with violent changes. This is one reason why change has not come more quickly to Black Americans as compared to other American minorities, because of the sharp difference in appearance between them and their white counterparts.

The expression "greater tolerance" ( Para. 1 ) refers to "______".

A．more respect for different beliefs and behaviors

B．quicker adaptation to changing circumstances

C．greater willingness to accept social change

D．greater readiness to agree to different opinions and idea

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题型：阅读理解

阅读理解。

The sea looks very beautiful when the sun is shining on it. But it can be very terrible when there is a

strong wind. The sea is very big. It covers three quarters of the earth. The sea is also very deep in some

places. In one place, the sea is about 11 kilometres deep. The highest mountain(山) in the world is about

nine kilornetres high. If that mountain was put into the sea at that place, there would still be two

kilometres of water above it!

In most parts of the sea,there are plenty of f ishes and plants (植物). Some live near the top of the

sea.Others live deep down. There are also a lot of small living things, and lots of fish live by eating them.

The sea can be very cold. When people go down, the sea becomes colder and colder. Only some men

can go down into the deep sea. But, in 1970, five women scientists lived in the deep sea for fourteen

days.

1. This writing is ________.

A. a short story

B. about the sea

C. a news report

D. a poem

2. Which of the following is NOT true?

A. The sea is usually very beautiful when it is sunny.

B. The sea is very terrible when the wind blows hard.

C. The highest mountain is in the deepest place of the sea.

D. The deeper the people go into the sea, the colder they would feel there.

3. The sea covers _________of the earth.

A. 1/3

B. 2/3

C. 1/4

D. 3/4

4. There are a lot of small living things in the sea,and_______.

A. they live by eating fish

B. they live to eat apples

C. they are good food for fish

D. they are too small for fish to catch

5. In 1970,five women lived in the deep sea for 14 days. That showed_______.

A. not only men can go down into the deep sea

B. women wanted to swim in the sea

C. women could go deeper into the sea than men

D. women liked living in the sea

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题型：选择题

number of visitors came but I don’t know number．

A．A ; the

B．The ; a

C．A ; a

D．The ; the

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题型：选择题

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题型：名词解释

症状

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微分方程y’+xy2-y2=1-x的通解为______．

题目：

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